Combination drug therapy has become a critical tool in the treatment of many disease states. Using two or more therapeutic agents with complementary mechanistic actions has been shown to hasten the resolution and reduce the severity of certain disease states more effectively than is possible with either agent alone. While exploiting the potential synergies between the agents and minimizing their side effects has always been the goal of combination drug therapy, combination strategies have also been shown to lower treatment failure, case-morbidity and mortality rates, slow the development of resistant or refractory cases, lower overall healthcare costs, and improve patients' overall quality of life. As our knowledge of the mechanisms of disease expands, advanced combination therapeutic strategies can improve the outcome of pharmaceutical intervention in these disease states.